Cold drawing a disk into a cap for paper core

ABSTRACT

A METAL COP FOR A PAPER CORE IS MADE BY THREE OPERATIONS: (1) DEPRESSING THE CENTRAL AREA OF A STEEL DISK TO FORM A SHALLOW CUP, (2) DEEPENING THE CUP AND SIMULTANEOUSLY FORMING A SOCKET IN THE WALL OF THE CUP, (3) CUTTING OUT THE CENTRAL PORTION OF THE BOTTOM OF THE CUP TO LEAVE AN INWARD BOTTOM FLANGE AND STRAIGHTENING THE FLANGE TO ADD TO THE LENGTH OF THE CYLINDRICAL WALL OF THE OBJECT. A SLIGHT RADIUS IS MAINTAINED AROUND THE END TO PERMIT INSERTION IN A CORE WHERE IT IS SUBSEQUENTLY EXPANDED.

Oct. 12, 1911 p CUSHING EIIAL 3,611,552

COLD DRAWING A DISK INTO A CAP FOR PAPER CORE "Filed March 9, 1970 2 Sheets-Sheet 1 F a G I 3 HNVENTOR PHILP S. CUSHNG HARRIS E. Sniff) 72,40,621 it ATTORNEY O 12, 1911 P. s. CUSHING ETAL 3,611,552

COLD DRAWING A DISK INTO A CAP FOR PAPER CORE Filed March 9, 1970 2 Sheets-Sheet a INVENTOR PHILIP S. CUSHING HARRIS E. STONE ATTORNEYS United States Patent 3,611,552 COLD DRAWING A DISK INTO A CAP FOR PAPER CORE Philip S. Cushing and Harris E. Stone, both of 293 lLenox St, Norwood, Mass. 02068 Continuation-impart of abandoned application Ser. No. 746,154, July 19, 1968. This application Mar. 9, 1970, Ser. No. 17,638

Int. Cl. B21d 39/04 U.S. Cl. 29-523 1 Claim ABSTRACT OF THE DISCLOSURE CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of U.S. application Ser. No. 746,154 filed July 19, 1968, now abandoned, by Philip S. Cushing et al. and entitled Cold Drawing a Disk Into a Cap for Paper Core.

This invention relates to metal caps for paper cores such as are used for rolls of newsprint and other kinds of paper. The cap hereinafter described is an improvement over that described and illustrated in our U.S. Pat. No. 3,291,413, granted Dec. 13, 1966, for Cap for Paper Core. A method of making the latter is claimed in our copending application Ser. No. 572,362, filed Aug. 15, 1966, now U.S. Pat. No. 3,449,817.

According to the present invention, a steel disk is cold drawn into a cup with cylindrical sidewalls and a socket on one side, the central portion of the bottom of the cup is cut or punched out, leaving an inward flange. This flange is substantially straightened out to form a continuation of the cylindrical wall, the final form being a cylindrical tube with a top flange of varying width, a socket projecting radially from the upper portion of the cylindrical wall and a slight bead or radius around the end to facilitate insertion in a core when it is subsequently straightened.

The successive stages by which the cap is formed, mounted and finished are illustrated on the drawing, of which FIG. 1 is a perspective view of a circular disk of sheet metal;

FIG. 2 is a perspective view of a shallow cup formed by cold drawing the disk shown in FIG. 1;

FIG. 3 is a sectional view of a deeper cup formed from the shallow cup by a cold drawing step, followed by the removal of the central area of the bottom of the cup;

FIG. 4 is a perspective view, on a reduced scale, of the finished cap;

FIG. 5 is a sectional side view of the finished cap,

FIG. 6 is a sectional side view of the cap mounted in a core; and,

FIG. 7 is a view similar to FIG. 6 showing the final shaping step.

In the following description of a method of making a cap, dimensions are given by way of illustration and not limitation for a cap to fit in an end of a standard paper core having a three-inch inner diameter.

The starting piece is a circular steel disk 10 which is 5 /2 inches in diameter. This is subjected first to a cold drawing step by which the central portion 11 of the disk, having a diameter of 3", is depressed about reducing the diameter of the disk to about 4 /8. The resulting step product 13, illustrated in FIG. 2, which is in the form of a shallow saucer with a plane rim 15 about Ms wide, is subjected to a second drawing operation to deepen the central depression to a depth of 1%", forming a cylindrical cup 12 with a narrower rim. By this second operation also a socket 14 is pressed outward, some of the metal for this socket being drawn from adjacent portions of the rim 15 so that the rim 18 varies from Zero extent on either side of the socket to a maximum diametrically opposite to the socket.

In the final drawing operation the central area of the bottom of the cup 12 is cut or punched out and the resulting inward flange 20 is straightened so that it becomes an extension 22 of the cylindrical wall of the cap which, as indicated in FIG. 4, is tubular with a top flange 18 of varying width, and a laterally projecting socket 14. The added length of the cap provides desirable stability when the cap is inserted in an end of a paper core.

As shown best in FIG. 5 the lower or inner edge of the cup is left with a slight bead or radius 24 which facilitates insertion of the cup into the end of a core 26 as shown in FIG. 7. Once seated in position, the bead 24 is smoothed out flush against the inner walls of the core by any one of a variety of devices such as an expandable chuck or the like. In FIG. 8 there is shown a rolling mechanism 28 which may be used for this purpose. The mechanism includes a rotatable tubular outer sleeve 30 formed with tapered openings 32 in a circle about its leading end, a central shaft 34 formed with a tapered end portion 36 and a plurality of hardened balls 38 trapped between the openings 32 and the portion 36. Rotation of the sleeve 30 together with an axial force applied to the shaft will cause the balls 38 to roll down the bead 24 until it is flush against the core walls.

We claim:

1. A method of making a cap for a paper core having a notch in an end of said core, which comprises (a) cold drawing a circular disk of sheet metal to form a shallow cup with cylindrical side walls and a wide plane rim,

(b) performing a second cold drawing operation on said cup to deepen said cylindrical cup and simultaneously to press a socket outward at the top of the cup, the metal for the socket being drawn from portions of said rim adjacent thereto whereby said plane rim is narrowed to vary from zero extent at said socket to a maximum diametrically opposite said socket, said socket being adapted to be assembled within said notch,

(c) removing the central area of the bottom of said cup to leave an inward flange,

(d) straightening said inward flange to form a cylindrical extension of the side walls of the cup and a bead about the end thereof,

(e) mounting said cap in said core, and,

(i) flattening said bead against said core.

References Cited UNITED STATES PATENTS RICHARD J HERBST, Primary Examiner U.S. Cl. X.R. 72-348 

